1. Field of the Invention
The present invention relates generally to calibration and testing of a transmitter (referred to herein as a data signal generator) and/or a receiver (referred to herein as a data signal receiver) and more particularly, to reduction in test time for performing the measurement of one or more parameters or properties of transmitted signals transmitted by a device under test (DUT) and/or received by a DUT.
2. Related Art
An electronic transmitter and/or receiver forms a basic component in mobile cell phones, wireless personal computers (PCs), and wireless devices in general. Typically, a wireless device is tested for acceptable performance before leaving production facilities. For example, part of the testing of the wireless device may include measuring quality parameters associated with a transmitted signal that is output by the wireless device and/or reception capabilities of the transmitted signal by the receiver of the wireless device.
Traditionally, production testing of a transmitter and/or receiver device has followed a sequential flow, testing one property of a transmitted or received signal at a time. The measurement capability of the testing equipment has in part driven the need for a sequential flow of testing. For example, typically, hundreds of data packet signals or packets are transmitted at a same transmitter setting or value for a property to be measured, e.g. the output power, to obtain an accurate measurement of the property due to the response time of the measurement system. For example, to obtain accurate results from a power meter, the device under test (DUT) or transmitter must send a same data packet signal or packet repeatedly while the power meter measures the power by averaging the measurements taken. The result is read back by the test system, and a decision is made regarding the next step of testing. If the power meter were to receive a transmission of data packet signals varying in output power, as versus receiving a transmission of packets at a same power level, the power meter would simply average the result, and not obtain a measurement of the output power of each transmission packet. Similar scenarios exist for other testing equipment, such as spectrum analyzers and other typical production measurement equipment for testing high frequency systems.
However, testing in such a sequential fashion increases the overall test time. For example, after transmission of a packet train of packets, e.g. several hundred packets, at a given output power, the power meter provides the output power measurement for the given output power setting of the transmitter. In order to obtain the transmitter's error vector magnitude (EVM) value for this power setting, another transmission of several hundred packets at the same transmitter power setting is output to be measured by EVM measuring equipment. After the EVM equipment obtains a value for the EVM for packets transmitted at the given output power setting of the transmitter, spectrum analyzer equipment may be employed to measure the spectral mask or spectral dissipation outside a predefined bandwidth. Again, several hundred packets are transmitted at the given power setting of the transmitter to allow the spectrum analyzer equipment to obtain a reading on the spectral mask for packets transmitted at the given output power.
An additional issue contributing to increased test time for testing transmission equipment and/or receiver equipment is that more modern transmitters and receivers are capable of transmitting and receiving data packet signals at multiple frequencies or data rates. Thus, the several properties to be measured, e.g. output power, EVM, and spectral mask, may need to be measured at multiple frequencies, besides multiple output power levels.
In view of the above, improvements are needed in determining measured values for multiple parameters or properties of a transmission of packets by a transmitter and/or reception capabilities by a receiver to receive the transmission of packets in a timely fashion. A need exists to produce the required measured values in a significantly lesser amount of test time than that offered by the traditional testing methods of the past.